%0 Journal Article
%T Effects of posture and vibration magnitude on seat to head transmissibility during exposure to fore
%A MK Bhiwapurkar
%A SP Harsha
%A VH Saran
%J Journal of Low Frequency Noise, Vibration and Active Control
%@ 2048-4046
%D 2019
%R 10.1177/1461348418756019
%X An experimental study has been conducted on the vibration simulator, developed as a mockup of a railway vehicle. In this paper, the effect of variations in the posture and vibration magnitude on head motions in three translational directions (fore-and-aft, lateral and vertical) are studied with seat vibration in fore-and-aft direction. Thirty healthy male subjects are exposed to random vibration with three vibration magnitudes of 0.4, 0.8 and 1.2 m/s2 r.m.s. over the frequency range 1¨C20£¿Hz. The data results are analyzed in terms of seat-to-head transmissibility (STHT) in two sitting postures; backrest and forward lean. Vibration measurements of the head motions are made with an apparatus (bite-bar). The study confirms that the measured responses to single fore-and-aft axis vibration have shown notable cross-axis responses. An increase in the excitation magnitude consistently revealed a decrease in the response peak magnitude and the corresponding resonant frequency, particularly in the presence of a back support. Such non-linear behavior has been interpreted as a non-linear softening effect in the muscle tension under increasing intensity of vibration. The use of a back support significantly alters the biodynamic responses of the seated body, which is attributable to the constraint due to the backrest support
%K Whole body vibration
%K seat to head transmissibility
%K biodynamic response
%K bite bar
%K rail vehicle
%U https://journals.sagepub.com/doi/full/10.1177/1461348418756019